1. Technical Field
The present invention relates to a wind turbine generator, more specifically, a wind turbine generator that includes a support column and a rotor with multiple canvas blades attached to the support column, the support column detachably fixed to an inner part of a circular ring and provided with tapered end portions, and that can be rotated by even weak wind force and can also be rotated continuously by inertial force after the rotation.
2. Background Art
In conventional wind power generation, propeller wind turbines and Darrieus wind turbines are the mainstreams of the horizontal axis wind turbines and the vertical axis wind turbines, respectively. However, it is said that these types of wind turbines can only deliver their performance with a wind speed of 10 m/s or faster.
Especially in wind power generation using propeller wind turbines, it has been inevitable that the entire wind turbine results in being large in size due to the following reason. A small wind turbine of this type rotates at 40 to 100 rpm. However, to use such a small wind turbine as a commercial wind turbine, the rated speed needs to be 900 to 1,750 rpm. Accordingly, the wind turbine has to be equipped with a speed-increasing gear that is used to increase the rated speed 20 to 60 times.
In addition, a disc or a brake is used for the control in strong winds to force the wind turbine to stop rotating, and this in turn causes an increase in price of the entire wind turbine. To improve these situations, a small and inexpensive wind turbine that is capable of increasing the rated speed by using a gear even when the wind force is weak has been developed (Japanese Patent Application Publication No. 2005-320865).
In contrast, Savonius wind turbines, paddle wind turbines and rotating-blade wind turbines are examples of wind turbines capable of generating power by weak winds. Such wind turbines are drag type wind turbines, and operate efficiently when the tip speed ratio (the peripheral speed of rotor/wind speed) is small while having a disadvantage of decreasing in operating performance when the tip speed ratio is large.
As a wind turbine for addressing these disadvantages, Japanese Patent Application Publication No. 2004-353637 discloses a “rotating-blade vertical axis wind turbine.” This rotating-blade wind turbine “includes canvas blades in a vertically-long shape, satisfying width:length=1:3 or larger, and each having a width 1.2 times or more longer than the length of the canvas blade frame to form a sag, and puts the power generator into operation by receiving wind force with lift force+drag force, causing sails having a high wind-receiving efficiency to rotate, and then causing a pinion for the power generator to rotate by the working of a rotation transmission gear.”
Japanese Patent Application Publication No. 2005-9415 discloses a “mechanism for automatically adjusting rotations of wind turbine.” In this mechanism, “canvas blades made of flexible and strong canvas are provided, yard members are attached respectively to the front ends and the back ends of the canvas blades, the front yard members are attached to a doughnut-shaped front hub member, the back yard members are attached to a doughnut-shaped back hub member to form a radial pattern, a rotation shaft is inserted into the hub members so as to protrude from the hub members, speed control balancers are attached to the back hub member with the rotation shaft interposed between the speed control balancers, connecting rods parallel with the rotation shaft are connected to a slide cylinder integrated with the front hub member, a spring bearing is provided to the front end of the rotation shaft, a return spring is elastically provided between the slide cylinder and the spring bearing, a long spiral hole is formed in the slide cylinder, a lock pin implanted in the rotation shaft in a standing position is loosely fitted into the long spiral hole, and torque of the rotation shaft is transmitted to the power generator.”
Patent Document 1 Japanese Patent Application Publication No. 2005-320865
Patent Document 2 Japanese Patent Application Publication No. 2004-353637
Patent Document 3 Japanese Patent Application Publication No. 2005-9415